Raman Suri C, Kaur Jasdeep, Gandhi Sonu, Shekhawat Gajendra S
Institute for Microbial Technology, Chandigarh 160036, India.
Nanotechnology. 2008 Jun 11;19(23):235502. doi: 10.1088/0957-4484/19/23/235502. Epub 2008 May 7.
The alarming increase in the amount of dangerous pesticides such as atrazine in agricultural fields and drinking water is driving the growth of new technologies to detect these toxins well below their threat level. The recent elucidation of microcantilever nanomechanical bending in response to chemical and biomolecular interactions has added another significant facet to biochemical engineering research and has fostered the development of a variety of signal detection paradigms, at both the microscale and the nanoscale. We report the label-free detection of highly specific atrazine antibody-antigen interactions at the nanometer scale on microcantilevers, with 1 ppt (past per trillion) sensitivity. The chemical interaction-induced deflection of the cantilever beam reflects the interplay between the strain energy increase of the cantilever and the free energy reduction of the reaction, providing a unique system for investigating the connection between the nanomechanics and the chemistry of antibody-antigen interaction at picomolar concentration with nanometer resolution. Cantilevers were functionalized with highly specific and site-directed anti-atrazine antibodies and exposed to target antigen over a wide range of concentration from 4.65 pM to 46.5 µM of varying sequence in static and flow conditions. Antibody-antigen interaction of atrazine with the specific antibody resulted in net negative deflection of the cantilever. The results show that high specificity and site-directed antibody immobilization lead to ultra-high sensitivity detection of atrazine. The measurements provide results within minutes at the picomolar level, and exhibit high target specificity. This qualifies the technology as a rapid method to validate organic toxins and its progression.
农田和饮用水中诸如阿特拉津等危险农药的含量惊人增长，这推动了新技术的发展，以便在远低于威胁水平的情况下检测这些毒素。最近对微悬臂梁纳米机械弯曲对化学和生物分子相互作用的响应的阐明，为生化工程研究增添了另一个重要方面，并促进了微尺度和纳尺度上各种信号检测范式的发展。我们报告了在微悬臂梁上以纳米尺度对高特异性阿特拉津抗体 - 抗原相互作用进行无标记检测，灵敏度达到1 ppt（万亿分之一）。悬臂梁的化学相互作用诱导的偏转反映了悬臂梁应变能增加与反应自由能降低之间的相互作用，为研究皮摩尔浓度下抗体 - 抗原相互作用的纳米力学与化学之间的联系提供了一个独特的系统，分辨率可达纳米级。悬臂梁用高特异性和位点定向的抗阿特拉津抗体进行功能化，并在静态和流动条件下，暴露于浓度范围从4.65 pM到46.5 μM、序列各异的目标抗原中。阿特拉津与特异性抗体的抗体 - 抗原相互作用导致悬臂梁产生净负偏转。结果表明，高特异性和位点定向的抗体固定化导致对阿特拉津的超高灵敏度检测。这些测量在几分钟内就能得到皮摩尔水平的结果，并且具有高目标特异性。这使该技术成为验证有机毒素及其进程的一种快速方法。
